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31.
1 Introduction Generallyknownasacodominantgeneticmarker ,microsatellitehasbeenwidelyusedinstudiesonpopu lationgenetics,high resolutiongenotyping ,genemap ping ,evolution ,linkageanalysis ,conservationbiology ,behaviouralecology ,relationsbetweenparasite…  相似文献   
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The mitochondrial DNA (mtDNA) control region was sequenced to examine the genetic variability and gene flow of juvenile Siganus spinus and S. guttatus. In total, 461 nucleotide sequences were obtained from 69 specimens of juvenile S. spinus from Okinawa Island and Ishigaki Island, in which 17 variable sites and 22 haplotypes were identified. Haplotype diversity (h) was high (0.9244 in Okinawa and 0.8984 in Ishigaki), whereas nucleotide diversity (π) was low (0.0063 in Okinawa and 0.0059 in Ishigaki). The two populations were not genetically distinct. Siganus guttatus, which do not form large schools at recruitment, in contrast S. spinus, were also analyzed by studying 152 individuals collected off Okinawa Island, Miyako Island, and Ishigaki Island. Of 476 nucleotide sequences, 50 were variable, and 42 haplotypes were identified. Genetic variability values were high (h = 0.8766 and π = 0.0151 in Okinawa; h = 0.9640 and π = 0.0192 in Miyako; h = 0.9161 and π = 0.0199 in Ishigaki). The Okinawa population was genetically isolated from the Miyako and Ishigaki populations. As a result, genetic diversity was high for each of these siganid populations despite their being target species for fisheries; however, the degree of inter-population gene flow was higher for S. spinus than S. guttatus, suggesting that these species exhibit different dispersal strategies.  相似文献   
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Constructed wetlands, especially mangroves, have been studied for their usefulness in sewage treatment but the effects of mangrove vegetation and a sewage load on mangrove macrofauna have been given little attention. Ocypodid crabs are important components of mangrove forests and constitute good bioindicators of the functioning of the ecosystem as a whole. In constructed mangrove mesocosms, three vegetation treatments (bare substratum, and Avicennia marina and Rhizophora mucronata seedlings) were subjected to 0, 20, 60 and 100% sewage loads from a nearby hotel. The physiological condition of introduced Uca annulipes and Uca inversa was evaluated in terms of their RNA/DNA ratio after one, five and twelve months, and used as an indicator of ecological function in the system. Crab condition in 0% sewage load was similar to that of wild crabs throughout, suggesting no significant effects of the mesocosms on their RNA/DNA ratio. Overall, both species coped well with the administered sewage loads, suggesting good ecological function in the system. Both species manifested similar patterns in RNA/DNA ratio, being more affected by seasonal fluctuations than by sewage load and vegetation presence and type. Higher RNA/DNA ratios were recorded in the long compared to the short rainy season. Sewage enhanced crab condition in the bare substratum and R. mucronata treatments, especially after one year, probably as a result of enhanced food availability. Uca inversa may be more sensitive to sewage pollution than U. annulipes. In A. marina, no difference in crab condition was observed between sewage loads, and this mangrove yielded the best reduction in sewage impacts. Our results support the usefulness of constructed mangrove areas in sewage treatment, especially if planted with A. marina and inhabited by physiologically healthy ocypodid crabs to enhance the system's performance.  相似文献   
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A total of 142 specimens of Ceramiales(Rhodophyta) were collected each month from October 2011 to November 2012 in the intertidal zone of the northwestern Yellow Sea. These specimens covered 21 species,14 genera,and four families. Cluster analyses show that the specimens had a high diversity for the three DNA markers,namely,partial large subunit r RNA gene(LSU),universal plastid amplicon(UPA),and partial mitochondrial cytochrome c oxidase subunit I gene(COI). No intraspecific divergence was found in our collection for these markers,except for a 1–3 bp divergence in the COI of Ceramium kondoi,Symphyocladia latiuscula,and Neosiphonia japonica. Because short DNA markers were used,the phylogenetic relationships of higher taxonomic levels were hard to evaluate with poor branch support. More than half species of our collection failed to find their matched sequences owing to shortage information of DNA barcodes for macroalgae in Gen Bank or BOLD(Barcode of Life Data) Systems. Three specimens were presumed as H eterosiphonia crispella by cluster analyses on DNA barcodes assisted by morphological identification,which was the first record in the investigated area,implying that it might be a cryptic or invasive species in the coastal area of northwestern Yellow Sea. In the neighbor-joining trees of all three DNA markers,H eterosiphonia japonica converged with D asya spp. and was distant from the other Heterosiphonia spp.,implying that H. japonica had affinities to the genus Dasya. The LSU and UPA markers amplified and sequenced easier than the COI marker across the Ceramiales species,but the COI had a higher ability to discriminate between species.  相似文献   
36.
Codium, one of the largest marine green algal genera, is difficult to delimit species boundary accurately based on morphological identification only. DNA barcoding is a powerful tool for discriminating species of seaweeds. The plastid elongation factor TU(tuf A) is considered as maker to perform DNA barcoding of green algal species than rbc L gene due to universality and rapid evolution rate. We conducted DNA barcoding application to Codium specimens from the Jeju Island, Korea to overcome the limit of morphological identification and to confirm the species diversity. As a result of applying tuf A marker, we newly generated fifty-five tuf A barcodes to resolve eight species. Tuf A marker exhibited 6.1%–21.8% interspecific divergences, wider than the gap of rbc L exon 1,3.5%–11.5%. Molecular analysis of rbc L exon 1 sequences of Codium revealed eight distinct species like tuf A analysis separated in five phylogenetic groups. DNA barcoding of the genus Codium using tuf A marker is more helpful to overcome the limit of morphological identification, and this is more potential to reveal cryptic species and to resolve the relationships among subspecies than rbc L analysis alone. The complement of tuf A barcoding and rbc L analyses including morphology for the genus Codium in the northwestern Pacific will give much more reliable achievement for discovering species diversity and resolving the phylogenetic relationships.  相似文献   
37.
DNA甲基化在调节动物生长发育和组织分化中发挥了重要作用。本研究主要从酶切、预扩和选扩等方面优化了中国对虾DNA甲基化分析的MSAP技术,给出了适合中国对虾MSAP分析的最近反应程序和体系,并采用该技术分别对中国对虾选育群体"黄海1号"和野生群体的肌肉、鳃和血细胞三种组织基因组DNA的CCGG甲基化水平进行分析。研究结果表明,中国对虾野生群体肌肉、鳃和血细胞的DNA甲基化比例分别为23.1%、22.3%和19.7%,选育群体"黄海1号"肌肉、鳃和血液的甲基化比例分别为21.4%、19.6%和18.9%。鳃组织的DNA甲基化水平在两群体中差异极显著(P <0.01),肌肉间的甲基化水平差异显著(P <0.05),而血细胞中甲基化水平差异不显著(P >0.05)。中国对虾野生群体和"黄海1号"同一组织间的甲基化水平不同(P ≤ 0.05),而不同组织间的甲基化水平也各不相同(P ≤ 0.05)。DNA甲基化多态性分析表明,野生群体和选育群体"黄海1号"的鳃和血细胞组织的甲基化多态性比例变化明显,而肌肉组织甲基化水平较稳定,这些变化趋势与CCGG位点的甲基化和去甲基化有关。  相似文献   
38.
根据GenBank中已知的条斑紫菜(Porphyra yezoensis)SSU和LSU r RNA基因序列分别设计引物,分别以混合个体和单个个体的基因组DNA以及c DNA为模板进行扩增,测序分析后推测SSU r RNA基因中的内含子转录后加工可能仍被保留,而在LSU r RNA基因上游序列中没有发现内含子。长511bp的内含子位于SSU r RNA基因序列的上游,其插入位点为TCTGGTG-CCAGCAGCC,内含子5′和3′端的核苷酸序列分别为AAC-和-ATGG。该内含子的剪接位点以及保守区P,Q,R,S与I型内含子是不同的。研究发现,在同种紫菜中,不同个体SSU基因中内含子的有无、分布及结构特征是不同的,说明内含子对于分类是不太适合的。但是内含子的长度以及核苷酸序列在种间又具有一定的特异性,可以为红藻种间以及种内亲缘关系较远的亚种和不同地理群的区分和鉴定提供参考。  相似文献   
39.
本研究旨在从DNA分子水平上研究中国鲎(Tachypleus tridentatus)种群遗传多样性及种群结构等相关信息,以期为保护其野生群体种质资源提供科学依据。本研究通过生物素—磁珠富集法筛选微卫星标记,构建中国鲎基因组微卫星文库。基因组DNA经Fast Digest Tru1I酶切后,选取400 bp~1000 bp片段,用生物素标记的(GT)15、(CT)15混合探针与其杂交,杂交复合物与链霉亲和素磁珠结合,捕获含有重复序列的微卫星片段,纯化后连接PMD19-T载体克隆,构建基因组微卫星文库。从334个阳性克隆中随机选取196个片段大于400 bp的阳性克隆进行测序,共获得127个微卫星序列,其中完美型占69.3%、非完美型占11.0%、复合型占19.7%。除探针使用的GT和CT的重复序列外,还筛选到多碱基GCT、TGG、AAAC、ACAA、GATTT、TTTTA的重复序列。根据微卫星序列设计选择合成40对引物,结果显示其中3对具有较高多态性,可作为进一步评价中国鲎野生种质资源等遗传信息的有效遗传标记。  相似文献   
40.
基因芯片技术在病原菌检测领域展现出良好的前景,本文依托水产病原菌基因检测芯片的检测体系,以水产常见病原弧菌的hsp60、toxR基因检测探针为研究对象,系统研究不同点样液配方、寡核苷酸探针浓度、荧光标记物质浓度、杂交温度、杂交时长对芯片杂交效果的影响,并进行相应优化。结果表明,杂交温度为60℃、杂交时长为2h、探针浓度为1μmol/L、Cy3标记的随机引物的用量为150pmol时,芯片的经济性、灵敏度、检测效率达到均衡;以0.1mol/L磷酸氢二钠和25%二甲基亚砜混合溶液作为点样液,效果较好。优化后的芯片对4种弧菌的检测没有出现交叉杂交现象,探针特异性达到100%;对溶藻弧菌全基因组DNA检测灵敏度为10fg,高出PCR方法约2个数量级。  相似文献   
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